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M.E. Super Ninja
Posts: 2312
 
| ChrisJC - 26/11/2012 20:45
Impressive as always. Just a shade dim for my tastes!!
So what is on the piece of veroboard?
Chris.
Sorry, I should have been more explicit.
Its the little module that gives 'power on' green LED, and 'low battery' red one.
Beauty of it is that by detecting the red LED at say full power ( which generates max drop on the cells) a user can fairly accurately judge the state of the battery. I have yet to come up with a guide for this, but my guestimate is that red LED at full power will probably mean that there is still 12 hours or more at walk mode. |
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M.E. Super Ninja
Posts: 2312
| State of the Lamps
With the end of 2012 coming close I have decided to upload a report on the current state of things. I have now dumped the idea of producing more powerful lamps as completely pointless. I am aiming more in the direction of making MagnumStars lighter and Trigons more reliable. EcoStars are good enough, full stop.
Upgrades
I have had quite a lot lately including one of the old UniStars, remember these?
Unfortunately, I am unable to increase the sustainable output of any low voltage (4V) lamp to a level greater than that of the EcoStar. (520 lumens)
I could probably get it up to a lot more than this based on a new battery pack with high quality cells such as genuine Sanyo fully charged but it would certainly not be sustainable for any time.
EcoStars
Since dumping the red Deans connectors there have been no returns at all on EcoStars sold this year, with exception of a brand new Oldham headset with a crack at the cable gland aperture which was unnoticed by me when assembling the lamp. I have had 1 charger returned. No battery failures either, but bear in mind they only have 2 cells so odds of a 4 cell Trigon pack having a duffer are double.
This reinforces my opinion that this is probably one of the most reliable lamps available.
Trigons
Emergency lights and floods have been the main issues. I have also had the 12V mains adaptors fail as well as the main drivers. I would say about a 4% failure rate. Beams now have a low current back up circuit which would probably still work with lamp full of water; this says a lot for simple linear drivers. This accounts for about 90 mA of the output and gives enough light to get out of anywhere.
There have been 2 instances of the Oldham switch contact springs failing, so I suppose ‘you know what’ happens. In truth a lot of lamps have been sold and things have to be viewed in that context. Most lamps sold have not given problems, but some customers have had 2 separate issues.
Emergency light issues have been addressed and I have been giving consideration to the issue of failure of the twin XPG floods; however the problem does seem to be dying out.
I am wondering about quality control issues with the XPGs?
In any event I am now reducing the drive current to 1.2 amps anyway, for an output of 780 lumens. If failures continue I intent to change over to a single XML. The existing driver can be set to output nearly 2 amps and would generate about 600 lumens from a single XML.
I have never ever had one of these drivers fail, or an XML emitter.
Customers who return lamps with failed floods will be given the XML option.
There have also been issues with the quality of some of the LiIon cells so now I tend to duration test power packs on the lamp they will ship with before potting and sealing.
If problems persist I will change over to genuine Sanyo cells, but this will necessitate a price increase.
MagnumStars
Very few of these are sold, 1 return with a wire that had become insecure and snagged on the rotating switch. I tried out the new model last weekend and the lighter weight was immediately noticeable. This pleases me.
I have already proved that thin copper conducts heat faster than thick aluminium.
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M.E. Super Ninja
Posts: 2312
| Trigon Floodlight Failures.
As I have posted before, I have now lowered the drive current from 1.46 amps to 1.2 amps causing the emitters to run slightly cooler. However, I have also remarked before that this could be due to quality control issues with the Cree XP-G emitters.
I have just noticed a change in the mounting of these emitters to the heat sink base, look at the pictures below. Ignore the burning on the one on the right, its been used for experimental purposes, but compare the base soldering. It appears that the manufacturers have beefed it up quite a bit.
What did I say?
 (xpquality.JPG)
Attachments
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 xpquality.JPG (59KB - 56 downloads)
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M.E. Foot Soldier
Posts: 118
| I guess it depends what the tracks were like on the previous MCPCBs (not obvious from the photo).
If the later board is XM-L-capable, one with only a single pad-to-LED track wouldn't necessarily be underspecced for an XP-G, and the solder pad for the XP-G on the earlier board does look like the recommended layout, assuming there is a line of solder under the edge of the device. |
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M.E. Super Ninja
Posts: 2312
| potholer - 1/2/2013 14:02
I guess it depends what the tracks were like on the previous MCPCBs (not obvious from the photo).
If the later board is XM-L-capable, one with only a single pad-to-LED track wouldn't necessarily be underspecced for an XP-G, and the solder pad for the XP-G on the earlier board does look like the recommended layout, assuming there is a line of solder under the edge of the device.
Sorry should have said, the XPGs are only 2mm footprint. I doubt that you would get an XML on the later board and in my opinion these boards are really too thin for safe heat dissipation from an XMP at up to 3 amps. I have yet to see an XML mounted on a board like these.
Edited by royfellows 1/2/2013 14:55
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M.E. Foot Soldier
Posts: 118
| You're right about the size difference, though it is possible to get XM-Ls on 10mm square or round boards the ones I've seen tend to have the pads very close to the LEDs.
Still, I'm not sure /exactly/ what's supposed to be wrong with the old board you pictured - most of my XPG MCPCBs from Cutter have pretty fine single tracks from pad to LED and that doesn't seem to cause problems.
The LED pad shape/size on your older boards isn't obviously wrong as far as can be told with the LED in place.
Possibly there are small pads underneath, or a bad thermal path from the heat pad through the board, or poor solder or reflowing, but it's not easy to tell by looking.
If solder power connections to the LED were good, even if they were smaller than ideal I'd wonder how much difference that might be expected to make? |
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M.E. Super Ninja
Posts: 2312
| As I have said in previous postings, I had one come away just by handling.
Originally, Cree gave a maximum drive current of 1 amp on these, and then published a new data sheet which said 1.5 amps. I now regard the upper drive currents as iffy.
Chris JC suggested that the solder may be melting due to excessive heat. I now think that he was partially right on this, hence me lowering the drive current. The failures have got to be due to a combination of several factors.
Interesting as well is that the problem now seems to be evaporating. |
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